1. Field of the Invention
The invention relates to a secondary battery temperature-increasing control apparatus, a vehicle including the same, and a secondary battery temperature-increasing control method. In particular, the invention relates to a technology for performing temperature increasing control to increase the temperature of the secondary battery with the use of the heat generation caused by the internal resistance of the secondary battery.
2. Description of the Related Art
In general, in secondary batteries, typified by lithium-ion batteries and nickel-hydrogen batteries, charging and discharging characteristics are degraded as the temperature decreases. When the temperature of the battery is low, it is required to quickly increase the temperature of the battery.
Japanese Patent Application Publication No. H11-26032 (JP-A-11-26032) describes an apparatus for healing up a battery for an electric vehicle. In this apparatus, the temperature of the battery is detected by a temperature sensor and a discharge controller performs control so that when the detected temperature is equal to or lower than a predetermined value, an output electric current greater than the requested electric current that the battery is requested to output is caused to flow.
It is insisted that with this heating up apparatus, it is possible to quickly increase the temperature of the battery to the inside thereof even in cold climate areas (see JP-A-11-26032).
In the above publication, however, neither the efficiency in increasing the temperature of the battery nor the state of the secondary battery after the temperature increase operation is performed is not discussed and it cannot be said that it is ensured that the optimum temperature increasing control is performed.